Setting up GitLab Development Kit (GDK)

Once you have the GitLab project ready, you can start working on the translation.

Tools

The following tools are used:

gettext_i18n_rails: this
gem allow us to translate content from models, views and controllers. Also
it gives us access to the following raketasks:

rake gettext:find: Parses almost all the files from the
Rails application looking for content that has been marked for
translation. Finally, it updates the PO files with the new content that
it has found.

rake gettext:pack: Processes the PO files and generates the
MO files that are binary and are finally used by the application.

gettext_i18n_rails_js:
this gem is useful to make the translations available in JavaScript. It
provides the following raketask:

rake gettext:po_to_json: Reads the contents from the PO files and
generates JSON files containing all the available translations.

PO editor: there are multiple applications that can help us to work with PO
files, a good option is Poedit which is
available for macOS, GNU/Linux and Windows.

Preparing a page for translation

We basically have 4 types of files:

Ruby files: basically Models and Controllers.

HAML files: these are the view files.

ERB files: used for email templates.

JavaScript files: we mostly need to work with Vue templates.

Ruby files

If there is a method or variable that works with a raw string, for instance:

defhello"Hello world!"end

Or:

hello="Hello world!"

You can easily mark that content for translation with:

defhello_("Hello world!")end

Or:

hello=_("Hello world!")

HAML files

Given the following content in HAML:

%h1 Hello world!

You can mark that content for translation with:

%h1=_("Hello world!")

ERB files

Given the following content in ERB:

<h1>Hello world!</h1>

You can mark that content for translation with:

<h1><%=_("Hello world!")%></h1>

JavaScript files

In JavaScript we added the __() (double underscore parenthesis) function that
you can import from the ~/locale file. For instance:

import{__}from'~/locale';constlabel=__('Subscribe');

In order to test JavaScript translations you have to change the GitLab
localization to other language than English and you have to generate JSON files
using bin/rake gettext:po_to_json or bin/rake gettext:compile.

Dynamic translations

Sometimes there are some dynamic translations that can't be found by the
parser when running bin/rake gettext:find. For these scenarios you can
use the N_ method.

Updating the PO files with the new content

Now that the new content is marked for translation, we need to update the PO
files with the following command:

bin/rake gettext:find

This command will update the locale/gitlab.pot file with the newly externalized
strings and remove any strings that aren't used anymore. You should check this
file in. Once the changes are on master, they will be picked up by
Crowdin and be presented for translation.

If there are merge conflicts in the gitlab.pot file, you can delete the file
and regenerate it using the same command. Confirm that you are not deleting any strings accidentally by looking over the diff.

The command also updates the translation files for each language: locale/*/gitlab.po
These changes can be discarded, the language files will be updated by Crowdin
automatically.

Discard all of them at once like this:

git checkout locale/*/gitlab.po

Validating PO files

To make sure we keep our translation files up to date, there's a linter that is
running on CI as part of the static-analysis job.

To lint the adjustments in PO files locally you can run rake gettext:lint.

The linter will take the following into account:

Valid PO-file syntax

Variable usage

Only one unnamed (%d) variable, since the order of variables might change
in different languages

All variables used in the message-id are used in the translation

There should be no variables used in a translation that aren't in the
message-id

Errors during translation.

The errors are grouped per file, and per message ID:

Errors in `locale/zh_HK/gitlab.po`:
PO-syntax errors
SimplePoParser::ParserErrorSyntax error in lines
Syntax error in msgctxt
Syntax error in msgid
Syntax error in msgstr
Syntax error in message_line
There should be only whitespace until the end of line after the double quote character of a message text.
Parseing result before error: '{:msgid=>["", "You are going to remove %{project_name_with_namespace}.\\n", "Removed project CANNOT be restored!\\n", "Are you ABSOLUTELY sure?"]}'
SimplePoParser filtered backtrace: SimplePoParser::ParserError
Errors in `locale/zh_TW/gitlab.po`:
1 pipeline
<%d 條流水線> is using unknown variables: [%d]
Failure translating to zh_TW with []: too few arguments

In this output the locale/zh_HK/gitlab.po has syntax errors.
The locale/zh_TW/gitlab.po has variables that are used in the translation that
aren't in the message with id 1 pipeline.

Adding a new language

Let's suppose you want to add translations for a new language, let's say French.

The first step is to register the new language in lib/gitlab/i18n.rb:

...AVAILABLE_LANGUAGES={...,'fr'=>'Français'}.freeze...

Next, you need to add the language:

bin/rake gettext:add_language[fr]

If you want to add a new language for a specific region, the command is similar,
you just need to separate the region with an underscore (_). For example:

bin/rake gettext:add_language[en_GB]

Please note that you need to specify the region part in capitals.

Now that the language is added, a new directory has been created under the
path: locale/fr/. You can now start using your PO editor to edit the PO file
located in: locale/fr/gitlab.edit.po.

After you're done updating the translations, you need to process the PO files
in order to generate the binary MO files and finally update the JSON files
containing the translations:

bin/rake gettext:compile

In order to see the translated content we need to change our preferred language
which can be found under the user's Settings (/profile).

After checking that the changes are ok, you can proceed to commit the new files.
For example: